Extensible mounting apparatus for hoists



March 15, 1966 J. E. JOYCE ETAL EXTENSIBLE MOUNTING APPARATUS FOR HOISTSFiled Aug. 27, 1962 4 Sheets-Sheet 1 FIG. I

INVENTORS JAMES E. JOYCE JACK D. NICHOLSON ATTORNEY March 15, 1966 J. E.JOYCE ETAL EXTENSIBLE MOUNTING APPARATUS FOR HOISTS Filed Aug. 27, 19624 Sheets-Sheet 2 FIG. 2

INVENTORS JAMES E. JOYCE JACK D. NICHOLSON /K ATTORNEY March 15, 1966 J.E. JOYCE ETAL EXTENSIBLE MOUNTING APPARATUS FOR HOISTS 4 Sheets-Sheet 3Filed Aug. 27, 1962 INVENTORS JAMES E. JOYCE .BY JACK D. NICHOLSONATTORNEY March 15, 1966 J. E. JOYCE ETAL EXTENSIBLE MOUNTING APPARATUSFOR HOISTS Filed Aug. 27, 1962 4 Sheets-Sheet 4 INVENTORS JAMES E. JOYCEBY JACK D. NICHOLSON ATTORNEY United States Patent 3,240,372 EXTENSIBLEMOUNTING APPARATUS FOR HOISTS James E. Joyce, Battle Creek, Mich, andJack D. Nicholson, Tulsa, Okla assignors to Clark Equipment Company, acorporation of Michigan Filed Aug. 27, 1962, Ser. No. 219,611 3 Claims.(Cl. 214-660) This invention relates to mounting apparatus for loadlifting hoists and the like, and more particularly to mounting apparatusfor hoists of a type which are extensible in a horizontal plane such asfor upright masts of industrial lift trucks of the type generally knownas reach or narrow-aisle lift trucks.

Warehousing of stacked palletized loads in rows with access aislesbetween rows necessitates insertion and removal of individual palletizedloads in a direction transverse of the aisle and between adjoiningstacks. To conserve space, narrow-aisle lift trucks have been marketedheretofore which can be turned in an aisle only slightly larger than thetruck wheel base and whose lifting fork can be retracted during normaltruck travel and projected during loading and unloading operations withthe components so arranged that the weight of the over-hanging projectedfork and its load is properly balanced to preclude tipping of thevehicle. Such trucks normally provide a U-shaped pocket at the one end,the legs or outriggers of which are supported at their free ends onground engaging wheels, and an upright and lifting fork assembly mountedfor longitudinal movement relative to said legs such that the liftingfork can be retracted within and extended beyond the U-shaped pocket. Atruck framework extends rearwardly of the base of the U-shaped pocketand provides traction means for the truck, as well as operator and truckcontrol means. With the fork in retracted position the load may betransported above the main frame and between the front and rear wheels.A truck of the aforementioned type is disclosed in detail in copendingapplication Serial No. 818,869, filed June 8, 1959, in the name ofRussell Hastings, Jr. (common assignee), now Patent No. 3,080,019.

In some job applications of lift trucks of the above-described type,which, it will be understood, merely exemplifies one of many uses whichmay be found for the present invention, it is required that theoutrigger legs, as well as the fork tines, be insertable beneath palletsand the like. In such applications it has been found that the height ofthe outrigger legs is as high or higher than the fork pockets of manypallets so that the outrigger legs cannot be inserted beneath suchpallets when the pallet is resting on the floor. As a result, there arecertain applications of such trucks wherein the truck cannot workefiiciently because of the above-mentioned limitation. The depth orvertical dimension of the outrigger legs of the U-shaped frame has beenheretofore largely determined by the relatively large diameter ofhorizontally spaced rollers which are conventionally mounted within thechannel sections which comprise said legs and are connected by suitablebracket means to the upright for supporting the upright for movementlongitudinally of the legs. Use of relatively small diameter uprightsupporting rollers of the above-mentioned type reduces the load carryingcapacity of the truck. It has, therefore, become important to deviseother means for supporting the upright during translation thereoflongitudinally of the outrigger legs while, at the same time, retainingthe full load carrying capacity of the truck and reducing substantiallythe vertical dimension of the outrigger legs.

We have devised a mounting assembly utilizing roller type chains whichare combined in a novel manner in out- 3,240,372 Patented Mar. 15, 1966upright mast or other construction which is translatable along saidlegs, and by means of which the vertical height of such legs may beminimized while the load carrying capacity of the upright remainssubstantially unaffected. Our invention provides a mounting assembly fortranslatable load lifting uprights wherein small diameter roller chainmechanism functions as relatively friction-free bearing means fortransmitting the load to the outrigger legs along the planes of contactof the chain mechanism with said legs.

It is therefore a primary object of the present invention to provide alift truck having improved mounting means for translatable load handlinghoists or uprights.

Another object of the invention is to provide a lift truck havingimproved mounting means for the lift truck up right which may beaccommodated in outrigger legs of substantially less height thanheretofore without adversely affecting load lifting capacity of thetruck.

A further object of the invention is to provide a lift truck havingimproved mounting means for elevating hoists of the type contemplatedwhich includes revolvable roller chain bearing structure through whichat least the forward thrust of a load carried by the hoist istransmitted to an elevator support assembly in which the elevator istranslatable.

Other objects, advantages and features of the present invention willbecome apparent from the following description when taken in conjunctionwith the accompanying drawings wherein:

FIGURE 1 is a side View in perspective showing the general arrangementof an industrial lift truck ofa type which is well suited to utilize thepresent invention;

FIGURE 2 is a partial view in perspectice of the lift truck shown inFIGURE 1 taken from one side and slightly to the rear thereof with theload lifting mast illustrated in an extended position;

FIGURE 3 is a broken-away perspective view of one of the outrigger legsof the truck showing one of the lifting mast mounting assemblies inmounted position within the outrigger leg;

FIGURE 4 is a perspective view of one roller chain mounting assembly perse taken from the outer side thereof;

FIGURE 5 is an enlarged broken-away partial longitudinal section of theroller chain mountingassembly and outrigger leg of the presentinvention;

FIGURE 6 is a partial assembly view of the roller chain used in thelifting mast mounting assembly;

FIGURE 7 is an enlarged broken-away front elevational view of anoutrigger leg such as shown in FIGURE 3, but which embodies a modifiedconstruction of the roller chain a mounting assembly as shown in FIGURE3.

FIGURE 8 is a perspective view similar to FIGURE 4 which shows amodification of the roller chain mounting assembly; and

FIGURE 9 is another perspective view similar to FIG- URE 4 showinganother modification of the roller chain mounting assembly.

Referring now in detail to FIGURES 1-5, the main frame of the wheeledtruck 5 is generally in the form of a. U-s-ha-pe, the projecting legs ofwhich are transversely spaced apart. Each outrigger leg consists of alongitudinally extending and inwardly opening channel construction 10upon each of which is mounted at its one end a trail wheel 12 upon astub shaft 13. The opposite ends of the legs are secured together bymeans of a transverse frame member, not shown. A lifting mast mechanismof known construction is illustrated at'numeral 14; it comrigger legs ofthe above-mentioned type for supporting an prises generally a pair oflaterally spaced apart outer fixed channel members 16, a pair oflaterally spaced I- beams 18 suitably nested within the channel membersfor vertical telescoping movement, a hydraulic cylinder lifting motor20, and a lifting carriage 22 mounted in known manner for verticalmovement relative to members 18 and connected to the hoist motor bymeans of conventional chain and sprocket mechanism, part of which isshown at numeral 21.. A pair of fork tines 30 are supported uponcarriage 22 and project forwardly thereof for engaging, transporting anddepositing loads in conjunction with horizontal movement of the truckand mast 14, and vertical movement of the carriage 22 within the mast.The mast construction 14 is disclosed in detail and claimed in copendingUS. continuation application Serial No. 111,070, filed May 18, 1961, inthe names of Hastings and Backofen (common assignee), now Patent3,213,967.

Suitably mounted within the framework of the truck and housed within therear corner portions of a body 24 is a pair of dirigible traction wheels26, one of which is shown, controllable by means of an operatorssteering wheel 28. The wheels 26 are driven by a pair of counterrotatingelectric motors, not shown. A generally U- shaped operator station 31 islocated at the rear end of the truck and is formed between rearwardlyextending vertical leg portions of control and body housing 24. Variousoperator controls in addition to steering wheel 28 are represented atnumeral 32, and include control means for operating the truck at variousspeeds, for braking the traction wheels 26, for elevating carriage 22 inmast 14, and for translating the mast longitudinally of outrigger legs10.

The construction of the lift truck has been described above in generalterms inasmuch as such construction per se does not comprise a part ofthe present invention, except as combined with the mounting constructionof the upright 14. The truck per se is exemplary only of one embodimentin which the present invention may be utilized to advantage.

Upright mechanism 14 is mounted upon a trolley 39 which spans the spacebetween legs and comprises a pair of longitudinally spaced transversebrace members 40 secured, as by welding, to a pair of transverselyspaced longitudinally extending L-shaped mounting members 42 which aresecured at the vertical legs, as by welding, to the outer surfaces ofthe webs of upright channel members 16 the latter being locatedlaterally between legs 10. Each of the legs 10 comprises alongitudinally extending channel section 44 having a cutout 46 at theforward end thereof for the reception of a wheel 12, the channel portionof the outrigger leg being of relatively small vertical dimension.Extending rearwardly of channel portion 44 is a box-shaped longitudinalframe portion 48 which is of substantially greater vertical dimensionthan the channel portion and which may be integral with the channelportion, as shown, or secured thereto at rear mating surfaces thereof,as by welding. Transverse frame members, not shown, extend between andare secured to portions 48 of legs 10, and the upwardly extending legsof body 24. are secured to the upper sides of leg portions 48.

Mounted within each channel portion 44 is an upright mounting and loadbearing assembly 50 comprising a longitudinally extending channel-shapedmember 52 nested within channel 44 such that it faces inwardly the sameas channel 44 and is of substantially smaller dimensions than theU-shaped opening formed by channel 44. The horizontal leg portion ofeach L-shaped support member 42 is secured, as by welding, to the inneredges 54 of the legs of the adjacent mounting channel 52, whereby themast assembly 14 and fork carriage 22 is supported in channel portions44 of legs 10 for movement in extension and retraction along the legs10. A hydraulic cylinder and piston assembly, the piston rod of which isshown at numeral 56 (FIG. 2) extends centrally and longitudinally of thetruck having the cylinder or base end thereof pivotally connected to atransverse frame member within body 24 and the rod end thereof pivotallyconnected to a mounting member 58 which is secured centrally of theforward transverse member 40 of trolley 39. When the cylinder isenergized from the base end piston rod 56 is extended which causes themast and carriage to be actuated in a forward direction from the FIG. 1to the FIG. 2 position thereof, whereas retraction of the piston r dcauses the mast and carriage to be actuated in a reverse direction, thelimits of movement being determined by the available stroke of rod 56and the length of mounting assemblies relative to the length of channelportions 44. The length of the track in each channel portion 44 is fixedby end plates 60 and 62 at the opposite ends thereof.

Referring now in greater detail to the construction of the mountingassemblies 50, as shown in FIGURES 3-6, each channel member 52 includesat each of the ends thereof a bifurcated extension 64 contiguous to theweb of the channel and in each of which is mounted for rotation about avertical pin 66 a side thrust roller 68, the periphery of whichextendsoutwardly somewhat beyond the web of channel 52 so that said webclears the web of channel 44 which engages the rollers 68 at all times.At each end of each flange of each channel section 52 and locatedtransversely intermediate each edge 54 and the adjacent bifurcatedportion 64 is a slot 70 having a rounded bearing surface 71. An endlessroller chain 72 of known construction is looped around each flangeportion of each channel member 52 and is threaded in slots 70 at theopposite ends of each said flange so that each said loop of roller chainis relatively taut when mounted as specified. The roller chainassociated with each flange of mounting channels 52 has the outer run ofits loop situated between the contiguous flanges of channels 52 and 44so that it functions as a roller thrust hearing which minimizes thefriction encountered during movement in either direction of channel 52relative to channel 44. During such movement each loop of roller chain72 is permitted to revolve in a continuous circuit with the cut-awayportion or slot 70 at opposite ends of each flange of channels 52forming a track which contains the loop of roller chain, the roundedends of said slots permitting the individual rollers of the rollerchains to revolve readily from one side of the flange to the other.

The construction of the roller chain is best illustrated in FIG. 6. Itcomprises a series of links 76 and another series of links 78. The links76 are pinned together in end to end relationship and in a similarfashion links 78 are joined in end to end relationship. The pins for thelinks 76 and 78 are illustrated at numeral 80 and rollers 82 arejournaled on these pins. Two such rollers 82 may be journaled on eachpin 80 to reduce skidding of the rollers due to variations inmanufacturing tolerances for the channels 44 and 52.

The roller chains 72 accommodate loads in a fore and aft direction, andend rollers 68 of the pair of channels 52 accommodate loads in atransverse direction. This is true in the construction above describedwhich contemplates use of square channel sections wherein the flanges ofeach channel 44 and 52 form approximately right angles with the websthereof so that the weight of the upright 14, carriage 22, and any loadcarried by fork tines 30 is transmitted to the flanges of the pair ofchannels 44 by way of trolley 39 through the pairs of upper and lowerloops of roller chain 72, thus producing a counterclockwise moment whichis resisted by channel 44, as viewed in FIG. 3. Eccentric loading of thefork tines, as when the greater part of a load carried thereby iscarried by one of the fork tines, produces side thrust or transverseloading which tends to twist upright 14 about a vertical axis. Suchtransverse loading is transmitted through trolley 39 and diagonallyrelated side thrust rollers 68 of opposite ones of upright mountingassemblies St the resulting transverse moment being resisted by oppositeones of the webs of channels 44. For example, as viewed in FIGS. 2 and3, an off-center load carried by the right hand fork tine produces atwisting moment which tends to rotate mast 14 in a clockwise directionabout a vertical axis, thereby producing a twisting mo ment which istransmitted to the webs of channels 44 through the forward roller 68 ofthe right hand mounting assembly 50 and through the rearward rollers 68of the left hand mounting assembly 50. Since all four of rollers 68 arepreferably in continuous abutment with the webs of respective channels44, mast 14 remains in fixed transverse relation to legs except possiblyfor slight twisting movement thereof which may result from a smallamount of deflection of the mounting assembly comprising trolley 39,channels 52 and outrigger legs 10. However, in a properly designedconstruction such deflection will be negligible and rollers 68 cooperateas aforesaid with legs 10 to maintain upright 14 in its desiredposition.

During extension of mast 14 in legs 10 it will be noted that the rollingfriction between roller chains 72 and the respective flanges of channels44 causes each upper chain 72 to revolve in a clockwie direction, asviewed in FIGS. 2 and 3, and each lower chain 72 to revolve in acounterclockwise direction. Retraction of mast 14 reverses the directionof rotation of each roller chain, as well as the direction of rotationof each roller 82 in each roller chain. It is desirable that in theconstruction of my invention the flanges of channels 52 be spaced fromthe flanges of channels 44, when the same are assembled in nestedrelation, such that rollers 82 of each roller chain 72 fit rather snuglyin the space provided so that a maxi-' mum number of rollers 82 of eachroller chain transmit a portion of a load carried by the fork tines tothe outrigger legs, whereby to maximize the area of bearing surfacebetween rollers 82 and the flanges of channels 44 when mast 14 issubjected to loading.

In light of the foregoing description it will now be apparent that ourinvention provides a translatable mounting structure for load hoistswhich tends to maximize the bearing surface area between the loadsupport platform, such as outrigger legs 10, and the surface area ofroller chains 72 in abutment therewith, while at the same time itprovides for rolling engagement between the bearing surfaces withrelatively little friction. Also, our invention permits the use of asupporting construction of relatively small vertical dimension in whichthe hoist is translatable without reducing the load carrying capacity ofthe hoist. In prior constructions used for this purpose, particularly innarrow-aisle type lift trucks as previously noted, it has been necessaryto utilize upright mounting means consisting of longitudinally spacedpairs of rollers mounted for rotation in the outrigger legs andsupporting the upright by suitable connecting means. Such priorconstruction results in a relatively small bearing area between thethrust rollers and the outrigger legs as determined by the points ofcontact therebetween, which necessitates the use of relatively largediameter thrust rollers with a consequent largevertical dimension of theoutrigger legs in which the thrust rollers are mounted. Priorconventional design in this regard appears in the aboveidentifiedcopending application of Hastings et al. which discloses outrigger legscomparable to legs '10 hereof but having a vertical dimensionsubstantially equal to the vertical dimension of rearward portion 48, asseen in FIG. 1 hereof.

A modification of my invention is shown in FIG. 7, in which partssimilar to those described above are similarly numbered. In theconstruction of FIG. 7 side thrust rollers 68 and the bifurcated end 64of the upright mounting channel assembly have been eliminated. The innerchannel configuration of flanges 90 of legs 10 includes innerlongitudinal surfaces 92 which slope in converging relation towards theweb of the channel section. Each upright mounting assembly includes abuilt-up channel section 94 having flanges 96 sloping at the same angleas surfaces 92 and located in inwardly spaced relation thereto forreceiving roller chains 72. An L-shaped bracket 42 is secured to theinner edges of flange 96 and a short web section 98 is secured betweenthe outer ends thereof. Slotted and rounded ends 70 are preferablyformed in flanges 96 the same as in the flanges of channels 52 forreceiving the roller chains in a similar manner. Secured at thetransverse outer end of each flange 96 is a longitudinal bar 100 whichprevents any tendency of the upper loop of roller chain to sag towardsthe web of leg 10 and of the lower loop of roller chain to skid towardssaid web as a result of side thrust imposed thereon by a load on thefork tines. Likewise, a pair of longitudinally extending bars 102 extendalong the opposite sides of the roller chains and are secured to theupper and lower surfaces of flanges 96 to prevent any tendency of thelower loop of roller chain to sag towards bracket member 42 and of theupper roller chain toskid under side thrust loading towards saidbracket. Pairs of bars 100 and 102 thus form with flanges 96 pairs oftracks for the loops of roller chain.

The roller chains in FIG. 7 are capable of accommo dating loads ineither a transverse or a fore and aft direction as a result of thechannel design, thus eliminating the need for extra side thrust rollers68. Since, in the embodiment of the invention herein described in usewith a narrow-aisle type lift truck, it is contemplated that theprincipal forces which act in a fore and aft direction will besubstantially greater than the forces acting in a transverse directionthe angle formed by the flanges of the respective channels with the webportions thereof is less than 135. If it is desired to increase thetransverse or lateral stability of the upright relative to the stabilityin a fore and aft direction, the angle of the flanges of the channelsrelative to the web sections thereof can be increased as required. Thesame advantages over the prior art inhere in both embodiments hereindescribed. It will be appreciated that, depending upon the particularapplication of the invention, the embodiment of either FIG. 3 or 7 maybe preferred.

FIGURE 8 shows a modification of the construction shown in FIG. 4wherein like parts have been similarly numbered. The embodiment of ourinvention illustrated in FIG. 8 differs from the FIG. 4 embodiment inthe use of a channel section having a cut-out center portion 112 suchthat a narrow portion 114 of the flanges of the channel section connectlongitudinally spaced channel portions 116, each of which carries a pairof upper and lower roller chains 118 mounted on and cooperating with theflange portions of each section 116 in a manner similar to the mountingof the roller chain 72 on the flanges of channel section 52. Side thrustrollers 68 are mounted for rotation in bifurcated end bracket portions64 the same as in FIG. 4. It will be understood that channel connectingflange portions 114 may be readily eliminated, if desired, and theroller chain mounting structure be constructed of two separate andindependent channel sections 116 connected along the inner edges thereofto L-shaped bracket 42. Also, the embodiment disclosed in FIG. 7 may bereadily modified as disclosed in FIG. 8 to provide separatelongitudinally spaced channel sections having biased flange portions inorder to eliminate the requirement of side thrust rollers 68.

Referring now to FIGURE 9, another modification of our invention isdisclosed wherein like parts have. been similarly numbered. Side thrustrollers 68 are mounted in longitudinally spaced relation on U-shapedbrackets 120 which are secured to the web portions of bracket 42. Upperand lower longitudinally extending L-shaped plate members are secured tobracket 42 in longitudinally spaced relation along short legs 122thereof. The outwardly extending leg portions 124 may be equivalent tothe upper rear flange portion and the lower forward flange portion ofthe front and rear channel sections 116 of FIG. 8. Support bars 125 addrigidity to the mounting structure, as shown. Roller chains 126 aremounted on each plate 124 in the manner described above previously.

It will be appreciated that in operation roller chains 72, as disclosedin the embodiments of "FIGS. 4 and 7, are not normally under thrustloading along the entire length of each roller chain in abutment withthe contiguous flange of leg 10. For example, when the fork 30 carries aload the forward thust imposes on the flanges of legs 10 an upwardlyextending force which is transmitted through. the rear portion of theupper run of roller chain 72 and a downwardly extending force which istransmitted through the forward portion of the lower run of roller chain72. Therefore it may be found desirable in utilizing the presentinvention to provide multiple roller chains which are of such a lengththat the loads transmitted thereby are distributed throughoutsubstantially the entire area of the respective lengths of chain inabutment with the contiguous portions of legs 10. Thus, in FIG. 8, theforward thrust of the mast 14 may distribute thrust loadingsubstantially throughout the ,area of the upper rear and lower forwardruns of chains 118, whereas a reverse thrust loading will be distributedsubstantially throughout the area of the lower rear and upper forwardruns of chains 118.

In FIGURE 9, a lower cost roller chain thrust mounting construction isprovided wherein chains 126 are adapted to transmit only forward thrustin that only upper rear and lower forward loops of roller chains areprovided in longitudinally spaced relation.

Although only a few embodiments of our invention have been illustratedand described in detail, it will be apparent to those skilled in the artthat various changes in the structure and relative arrangement of partsmay be made to suit individual requirements without departing from thescope of the invention.

We claim:

1. An industrial truck comprising a horizontal wheel supported U-shapedframe, outrigger legs of said frame extending longitudinally forwardlyin parallel spaced relation to each other and having channel sectionsopening inwardly in facing relation to each other, a rear transverseframe portion connecting together the rear ends of said outrigger legsto form said U-shaped frame, the forward portion of said outrigger legsbeing of substantially less height than said rear ends thereof forfacilitating entry of said forward portions beneath low height loadsupporting pallets and the like, upwardly extending load lifting meansmounted within the pocket formed by the U-shaped frame for movementlongitudinally thereof, a pair of mounting means of substantially lesslength than the channel sections of the outrigger legs nested within therespective channel sections of the legs of said frame, each mountingmeans including relatively closely vertically spaced upper and lowerflange members nested within one of the channel sections and extendinglongitudinally thereof, an endless loop of linked roller'chain mountedfor revolution longitudinally of each flange member and adapted totransmit forces imposed on the lifting means to the respective channelsection, a plurality of rollers in each said roller chain being adaptedto divide and distribute to the respective channel section the totalforce transmitted thereby, the upper roller chain being adapted totransmit an upwardly directed force to each upper portion of thecontiguous channel section and the lower roller chain being adapted totransmit a downwardly directed force to the lower portion of saidchannel section, said chain of rollers which is looped longitudinally ofeach flange member being revolvable around the flange member in adirection opposite to the direction of revolution of the cooperatingchain of rollers during movement of the load lifting meanslongitudinally of the frame and each roller of each, roller chain beingrevolvable about its own axis, each roller of said roller chains beingof relatively small diameter to facilitate the use of said relativelylow height forward portions of said outrigger legs, a longitudinallyextending generally L-shaped bracket means connected to both upper andlower flange members of each mounting means transversely inwardly of themounting of the roller chains thereon and secured to opposite sides ofsaid load lifting means for supporting said load lifting means on saidmounting means for movement longitudinally of said outrigger legs, meansfor actuating the load lifting means and mounting means longitudinallyof said outrigger legs, and a pair of relatively large diameter trucksupport wheels mounted at the forward ends of said outrigger legs.

2. A vehicle as claimed in claim 1, wherein each said mounting means ofwhich said flange members are a part comprises an inwardly openingchannel member, said chains of rollers being mounted on said flangemembers of each channel member, bracket means extending forwardly andrearwardly of each channel member, and a thrust roller mounted in eachsaid bracket means and adapted to transmit thrust forces to therespective vertical portions of the channel sections of said outriggerlegs.

'3. A vehicle as claimed in claim 1 wherein the channel sections of saidoutrigger legs include inner flange surfaces which diverge at apredetemined angle in a direction transversely inwardly of the vehicle,the flange members of each said mounting means being located insubstantially parallel relation to said flange surfaces, said rollerchains being disposed between each said flange member and inner flangesurfaces for transmitting to said channel sections both forward and sidethrust forces.

References Cited by the Examiner UNITED STATES PATENTS 206,648 7/ 1878Tucker. 2,033,649 3/1936 Rendleman et a1. 2,320,601 6/1943 Howell 187-9X 2,643,740 6/ 1953 Quayle l-879 2,664,970 1/1954 Warshaw 187--92,881,031 4/1959 Comfort 308-6 2,889,181 6/ 1959 Lang et a1. 2,925,1502/1960 Sanders 187-76 2,962,980 12/ 1960 Carrigan. 3,014,344 12/1961Arnot 187-9 X 3,031,091 4/1962 Erickson et a1 1879 X 3,061,045 10/1962Gunning 1879 FOREIGN PATENTS 730,922 5/ 1932 France.

1,078,502 3/1960 Germany.

SAMUEL F. COLEMAN, Primary Examiner. ANDRES H. NIELSEN, Examiner.

1. AN INDUSTRIAL TRUCK COMPRISING A HORIZONTAL WHEEL SUPPORTED U-SHAPEDFRAME, OUTRIGGER LEGS OF SAID FRAME EXTENDING LONGITUDINALLY FORWARDLYIN PARALLEL SPACED RELATION TO EACH OTHER AND HAVING CHANNEL SECTIONSOPENING INWARDLY IN FACING RELATION TO EACH OTHER, A REAR TRANSVERSEFRAME PORTION CONNECTING TOGETHER THE REAR ENDS OF SAID OUTRIGGER LEGSTO FORM SAID U-SHAPED FRAME, THE FORWARD PORTION OF SAID OUTRIGGER LEGSBEING OF SUBSTANTIALLY LESS HEIGHT THAN SAID REAR ENDS THEREOF FORFACILITATING ENTRY OF SAID FORWARD PORTIONS BENEATH LOW HEIGHT LOADSUPPORTING PALLETS AND THE LIKE, UPWARDLY EXTENDING LOAD LIFTING MEANSMOUNTED WITHIN THE POCKET FORMED BY THE U-SHAPED FRAME FOR MOVEMENTLONGITUDINALLY THEREOF, A PAIR OF MOUNTING MEANS OF SUBSTANTIALLY LESSLENGTH THAN THE CHANNEL SECTIONS OF THE OUTRIGGER LEGS NESTED WITHIN THERESPECTIVE CHANNEL SECTIONS OF THE LEG OF SAID FRAME, EACH MOUNTINGMEANS INCLUDING RELATIVELY CLOSELY VERTICALLY SPACED UPPER AND LOWERFLANGE MEMBERS NESTED WITHIN ONE OF THE CHANNEL SECTIONS AND EXTENDINGLONGITUDINALLY THEREOF, AN ENDLESS LOOP OF LINKED ROLLER CHAIN MOUNTEDFOR REVOLUTION LONGITUDINALLY OF EACH FLANGE MEMBER AND ADAPTED TOTRANSMIT FORCES IMPOSED ON THE LIFTING MEANS TO THE RESPECTIVE CHANNELSECTION, A PLURALITY OF ROLLERS IN EACH SAID ROLLER CHAIN BEING ADAPTEDTO DIVIDE AND DISTRIBUTE TO THE RESPECTIVE CHANNEL SECTION THE TOTALFORCE TRANSMITTED THEREBY, THE UPPER ROLLER CHAIN BEING ADAPTED TOTRANSMIT AN UPWARDLY DIRECTED FORCE TO EACH UPPER PORTION OF THECONTIGUOUS CHANNEL SECTION AND THE LOWER ROLLER CHAIN BEING ADAPTED TOTRANSMIT A DOWNWARDLY DIRECTED FORCE TO THE LOWER PORTION OF SAIDCHANNEL SECTION, SAID CHAIN OF ROLLERS WHICH IS LOOPED LONGITUDINALLY OFEACH FLANGE MEMBER BEING REVOLVABLE AROUND THE FLANGE MEMBER IN ADIRECTION OPPOSITE TO THE DIRECTION OF REVOLUTION OF THE COOPERATINGCHAIN OF ROLLERS DURING MOVEMENT OF THE LOAD LIFTING MEANSLONGITUDINALLY OF THE FRAME AND EACH ROLLER OF SUCH ROLLER CHAIN BEINGREVOLVABLE ABOUT ITS OWN AXIS, EACH ROLLER OF SAID ROLLER CHAIN BEING OFRELATIVELY SMALL DIAMETER TO FACILITATE THE USE OF SAID RELATIVELY LOWHEIGHT FORWARD PORTIONS OF SAID OUTRIGGER LEGS, A LONGITUDINALLYEXTENDING GENERALLY L-SHAPED BRACKET MEANS CONNECTED TO BOTH UPPER ANDLOWER FLANGE MEMBERS OF EACH MOUNTING MEANS TRANSVERSELY INWARDLY OF THEMOUNTING OF THE ROLLER CHAINS THEREON AND SECURED TO OPPOSITE SIDES OFSAID LOAD LIFTING MEANS FOR SUPPORTING SAID LOAD LIFTING MEANS ON SAIDMOUNTING MEANS FOR MOVEMENT LONGITUDINALLY OF SAID OUTRIGGER LEGS, MEANSFOR ACTUATING THE LOAD LIFTING MEANS AND MOUNTING MEANS LONGITUDINALLYOF SAID OUTRIGGERR LEGS, AND A PAIR OF RELATIVELY LARGE DIAMETER TRUCKSUPPORT WHEELS MOUNTED AT THE FORWARD ENDS OF SAID OUTRIGGER LEGS.